Synthesis of amino allenes via reaction of alpha-aminoalkylcuprates with propargyl substrates

alpha-Aminoalkylcuprates prepared from carbamates via sequential deprotonat ion and treatment with CuCN . 2LiCl react with propargyl bromides, mesylate s, tosylates, acetates, and epoxides to afford amino allenes via a S(N)2' s ubstitution process. Propargyl bromides and sulfonates give good yields of amino allenes while the acetates afford low yields. Substrates undergo regi ospecific S(N)2' substitution and the use Sc(OTf)(3) affords improved yield s of amino allenes from propargyl epoxides. The Boc protected alpha-amino a llenes can be cyclized to oxazolidones or deprotected to afford the free am ines. (C) 1999 Elsevier Science Ltd. All rights reserved.